To develop lithium ion secondary batteries with high capacity, high reliability, and long life, it is essential to evaluate the stability of the electrode materials during the charge/discharge process. The laminate cell attachment enables to reproduce a high-speed charge/discharge process while keeping the sample temperature constant, and simultaneously to collect transmission X-ray diffraction images. By using this attachment with an X-ray diffractometer equipped with a Mo X-ray source and a 2D detector collecting a maximum of 131 diffraction images per second, it becomes possible to observe the rapid phase transition occurring inside the battery cell.